You might need to end all active data sessions either by entering airplane mode, restarting your phone or turning data on and off and then starting again. I had a similar problem where after I purchased a bundle i needed to switch my phone of and on again!

When companies like Techzim market Econet products like Facebook USSD, they must surely ask simple questions like :
1) How does one deactivate this USSD on facebook
2) How much does it cost
3) Has it been tested in similar environments
4) Are there limitations - like how much data is in Facebook Lite/Whatsapp Lite
5) What is the maximum(mb's) an intensive user can get from Facebook Lite etc.